Seed dormancy, an important adaptive trait that governs germination timing, is endogenously controlled by phytohormones and genetic factors. DELAY OF GERMINATION 1 (DOG1) is the vital genetic regulator of dormancy, significantly affecting the expression of numerous ABA and GA metabolic genes. However, whether DOG1 could influence the expression of other phytohormone-related genes is still unknown. Here, we comprehensively investigated all well-documented hormone-related genes which might be affected in dog1–2 dry or imbibed seeds by using whole-transcriptome sequencing (RNA-seq). We found that DOG1 could systematically control the expression of phytohormone-related genes. An evident decrease was observed in the endogenous signal intensity of abscisic acid (ABA) and indole-3-acetic acid (IAA), while a dramatic increase appeared in that of gibberellins (GA), brassinosteroids (BR), and cytokinin (CK) in the dog1–2 background, which may contribute considerably to its dormancy-deficient phenotype. Collectively, our data highlight the role of DOG1 in balancing the expression of phytohormone-related genes and provide inspirational evidence that DOG1 may integrate the phytohormones network to control seed dormancy.

Phenanthrene (PHE) is a typical compound biomagnified in the food chain which endangers human health and generally accumulates from marine life. It has been listed as one of the 16 priority PAHs evaluated in toxicology. In order to evaluate the changes of CYP1A GST mRNA expression and EROD GST enzyme activity in carp exposed to lower than safe concentrations of PHE. Long-term exposure of carp to PHE at lower than safe concentrations for up to 25 days. The mRNA expression level and cytochrome P450 (CYP1A/EROD (7-Ethoxylesorufin O-deethylase)) and glutathione S-transferase (GST) activity were measured in carp liver and brain tissue. The results showed that PHE stress induced low-concentration induction and high-concentration inhibition of CYP1A expression and EROD enzyme activity in the liver and brain of carp. In both two organs, GST enzyme activity was also induced. However, the expression of GST mRNA was first induced and then inhibited, after the 15th day. These results indicate that long-term exposure to PHE at lower than safe concentrations still poses a potential threat to carp’s oxidase system and gene expression.

To optimize offspring seed survival in fluctuating environments, seed plants have evolved two key adaptive strategies, seed dormancy under favorable conditions and germination arrest under stress, to control germination timing. The phytohormone abscisic acid acts as a master regulator in both processes, exerting precise control over its endogenous levels and signaling to fine-tune this seed-seedling transition. Previously, we identified ODR1 as a key seed dormancy regulator: it negatively modulates seed dormancy by suppressing ABA accumulation during seed development via inhibiting bHLH57-dependent transcriptional activation of the ABA biosynthesis genes NCED6/9. However, whether ODR1 also modulates seed germination under stress conditions remains unknown. Here, we showed that loss of ODR1 function arrested seed germination under osmotic stress, while specific overexpression of ODR1 in odr1 mutant seeds rescued this osmotic germination arrest. Osmotic stress induced and maintained high ODR1 expression, but this induction was reduced in the ABA biosynthesis-deficient mutant nced6/9 and ABA signaling mutants abi3-1, abi4-t, and abi5-8, indicating ABA dependence of ODR1 induction. In odr1 mutants, 8 out of 12 key ABA biosynthesis genes were significantly upregulated. ChIP-seq data analysis revealed an ODR1 binding peak in the promoter of the ABA biosynthesis gene ABA1. Specific overexpression of ODR1 in odr1 mutant seeds notably rescued the upregulated ABA1 expression, confirming the repression of ABA1 by ODR1. Furthermore, ABA content was significantly increased in germinating seeds of odr1 mutant, and exogenous application of fluridone, an ABA biosynthesis inhibitor, effectively rescued their germination arrest, linking the phenotype to excessive ABA accumulation. These results reveal a novel role of ODR1 in osmotic stress-induced germination arrest: ODR1 is induced by osmotic stress via an ABA-dependent pathway and in turn limits ABA accumulation via repressing the expression of ABA biosynthesis genes, thereby alleviating germination arrest under stress. Together, we demonstrate that ODR1 coordinates germination timing via ABA-dependent negative feedback regulation of ABA biosynthesis during both dormancy establishment and osmotic stress responses. This mechanism addresses the critical question of how plants fine-tune ABA signaling to balance survival and germination in variable environments.

Small-grained rice varieties are highly valued in hybrid seed production and food markets because of their unique advantages in mechanized seed production and cooking qualities. Developing new varieties combining small grain size with high nutritional and cooking quality represents an important breeding objective. The OsVIN2 gene has been identified as a key regulator involved in carbohydrate metabolism and grain development in rice. In this study, a CRISPR/Cas9-mediated gene-editing approach was employed to precisely modify the OsVIN2 gene in the restorer line MH86 of high-quality rice varieties. Compared with the wild-type plants, the frameshift mutant seeds showed a significant reduction in length and width by 19.9% and 15.2%, respectively, leading to a 39.2% decrease in thousand-grain weight. Notably, the mutant exhibited improved quality traits, including a decrease of 16.6% in amylose content, an increase of 11.0% protein, and a 77.5% and 84.7% decrease in chalkiness rate and chalkiness degree, respectively. These results demonstrate that targeted editing of OsVIN2 is a promising approach for creating novel small-grained rice germplasm with superior quality attributes.